How do I solve two simultaneous equations?
Supposing we have two equations x+2y=5 and 3x-y=10 and we want to find x and y we can use the following techinque. Multiply both the RHS and the LHS of the second equation by 2, giving us 6x-2y=20. Then add this to the first equation, giving us 7x=25 thus x=25/7. The substitute the value for x to find y: 25/7 +2y=5 => y=5/7. Alternatively, we can manipulate the first equation to give us x=5-2y and substitute in the second equation: 15-6y-y=10 => -7y=-5 =>y=5/7 and then substitute in the first equation to find x. Remember, to find the value of n variables we need n equations, except in special cases.
TX
Related Maths GCSE answers
All answers ▸Bob sprints down a 100 metre track as fast as he can and as he arrives at the finish, a light gate cuts a timer that has been active since Bob began his sprint. It reads 12.45 seconds. calculate Bobs average speed during the sprint.
The equation of line L1 is y=3x-5. The equation of line L2 is 2y-6x+5=0. Show that these two lines are parallel.
Simplify fully 3/(2x + 12) - (x - 15)/(x^2 - 2x - 48)
There are some people in a cinema. 3/5 of the people in the cinema are children. For the children in the cinema, number of girls:number of boys = 2:7. There are 170 girls in the cinema. Work out the number of adults in the cinema.